When Emile Leray's Citroën 2CV car broke down in the middle of the
Sahara Desert, he couldn't build an arc reactor to fit into his flying
suit of armor, so he did the next best thing: he stripped down to his
manthong and converted the car into a Mad Max-ian motorcycle!

While traveling through the desert somewhere in north west Africa
in his Citroen 2CV , [Emile] is stopped, and told not to go any further
due to some military conflicts in the area. Not wanting to actually
listen to this advice, he decides to loop around, through the desert,
to circumvent this roadblock.

After a while of treading off the beaten path, [Emile] manages
to snap a swing arm on his vehicle, leaving him stranded. He decided
that the best course of action was to disassemble his vehicle and construct
a motorcycle from the parts. This feat would be impressive on its own,
but remember, he’s still in the desert and un-prepared. If we’re
reading this correctly, he managed to drill holes by bending metal and
sawing at it, then un-bending it to be flat again.

I was doubtful when I read the summary, but the account on his web page is pretty convincing.

He was apparently not new to the idea of converting 2CVs into other things (he made a boat out of another one before that), and he was going for a solitary raid in the desert, hence the water and spare parts. No welding was involved apparently, everything being held together by screws.

After he finished it, he was arrested for driving a non-conform vehicle and had to guide the police to the rest of his car to convince them of his story. The report written after the arrest (procès verbal) is on the site too (chameaudacier.free.fr/pv.jpg).

@Astrogoth where are the extra parts you speak of? I can see nothing obvious on there that isn't a 2CV part. Nor do I see any need for welding. An excelent fab job and the friction drive to the rear wheel is remarkably inventive.